We report Hall measurement of the normal state in K- and Co-doped BaFe$_2$As$_2$, as well NaFe$_{1-x}$Co$_x$As. We found that a power-law temperature dependence of Hall angle, cot$theta_{rm H}$$propto$ $T^beta$, prevails in normal state with temperature range well above the structural, spin-density-wave and superconducting transitions for the all samples with various doping levels. The power $beta$ is nearly 4 for the parent compounds and the heavily underdoped samples, while around 3 for the superconducting samples. The $beta$ suddenly changes from 4 to 3 at a doping level that is close to the emergence of superconductivity. It suggests that the $beta$ of $sim 3$ is clearly tied to the superconductivity. Our data suggest that, similar to cuprates, there exists a connection between the physics in the normal state and superconductivity of iron-pnictides. These findings shed light on the mechanism of high-temperature superconductivity.
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